Jesmer attributes Mourdock's success to his "good platform" that "struck a tone with Hoosiers." Currently Indiana's state treasurer, Mourdock's platform focused largely on the size of government, the national debt, and the idea that compromise with Democrats is a bad idea.

Part of Mourdock's success can be pinned on the fact that outside political action committees (PACs) spent millions of dollars backing his campaign. The national Tea Party organization FreedomWorks spent more than $580,000 backing him, and the conservative group Club for Growth says in total it backed Mourdock's run with $2 million in ads, mail and bundling.

Jesmer acknowledged the potential power of PACs in all campaigns. He said, "from a technical point of view," the advent of super PACs is one of the NRSC's toughest challenges. PACs have the ability to take control of the narrative away from candidates, so the NRSC is careful to tell all its candidates, "Try being in control of your narrative and have a rationale for your candidacy."

Though losing a sitting senator in Indiana wasn't the NRSC's preferred outcome, Republicans are confident that Mourdock will keep the seat in November.

Holding Indiana means that Republicans only need to pick up four seats to take control of the Senate. Of 33 seats up for grabs, 23 are Democratic or independent caucusing with the Democrats. Jesmer feels good about Senate races in North Dakota, Nebraska, Missouri, Montana, Wisconsin and even Hawaii as pick-up opportunities.

Massachusetts is one place where Republicans face a tough battle to hold a seat, as Senator Scott Brown is facing a tough challenge from Elizabeth Warren, the former adviser to President Obama who helped set-up the Consumer Financial Protection Bureau. Overall though, Jesmer feels pretty confident about winning back control, saying, "I think we've got a great chance of taking the Senate."